1. Field of Disclosure
The present disclosure relates generally to improvements in methods of and apparatus for checking out products in point-of-sale (POS) environments.
2. Brief Description of the State of Knowledge in the Art
The use of bar code symbols for product and article identification is well known in the art. Presently, various types of bar code symbol scanners have been developed for reading bar code symbols at retail points of sale (POS).
Also, over the years, electronic article surveillance (EAS) methods have been developed to prevent shoplifting in retail stores or pilferage of books from libraries. Special tags are fixed to merchandise or books. These tags are removed or deactivated by the clerks when the item is properly bought or checked out at a POS station. At the exits of the store, a detection system sounds an alarm or otherwise alerts the staff when it senses “active” tags. For high-value goods that are to be manipulated by the patrons, wired alarm clips may be used instead of tags.
Currently, several major types of electronic article surveillance (EAS) systems have been developed, namely: magnetic-based EAS systems, also known as magneto-harmonic; acousto-magnetic based EAS systems, also known as magnetostrictive; radio-frequency based EAS systems; and microwave-based EAS systems.
Magnetic-Based EAS Systems
In magnetic-based EAS systems, the tags are made of a strip of amorphous metal (metglas), which has a very low magnetic saturation value. Except for permanent tags, this strip is also lined with a strip of ferromagnetic material with a moderate coercive field (magnetic “hardness”). Detection is achieved by sensing harmonics and sum or difference signals generated by the non-linear magnetic response of the material under a mixture of low-frequency (in the 10 Hz to 1000 Hz range) magnetic fields. When the ferromagnetic material is magnetized, it biases the amorphous metal strip into saturation, where it no longer produces harmonics. Deactivation of these tags is therefore done with magnetization. Activation requires demagnetization. This type of EAS system is suitable for items in libraries since the tags can be deactivated when items are borrowed and re-activated upon return. It is also suitable for low value goods in retail stores, due to the small size and very low cost of the tags.
Acousto-Magnetic Based EAS Systems
These EAS systems are similar to magnetic-based EAS systems, in that the tags are made of two strips of metal, namely: a strip of magnetostrictive, ferromagnetic amorphous metal, and a strip of a magnetically semi-hard metallic strip, which is used as a biasing magnet (to increase signal strength) and to allow deactivation. These strips are not bound together, but are free to oscillate mechanically. Amorphous metals are used in such systems due to their good magneto-elastic coupling, which imply that they can efficiently convert magnetic energy to mechanical vibrations. The detectors for such tags emit periodic tonal bursts at about 58 kHz, the same resonance frequency as of the amorphous strips [3]. This causes the strip to vibrate longitudinally by magnetostriction, and to continue to oscillate after the burst is over. The vibration causes a change in magnetization in the amorphous strip, which induces an AC voltage in the receiver antenna. If this signal meets the required parameters (correct frequency, repetition etc.) the alarm is activated.
When the semi-hard magnet is magnetized, the tag is activated. The magnetized strip makes the amorphous strip respond much more strongly to the detectors, because the DC magnetic field given off by the strip offsets the magnetic anisotropy within the amorphous metal. The tag can also be deactivated by demagnetizing the strip, making the response small enough so that the detectors will not detect it. These tags are thicker than magnetic tags and are thus seldom used for books. However they are relatively inexpensive and have better detection rates (fewer false positives and false negatives) than magnetic tags.
Radio-Frequency Based EAS Systems
The Series 304 RF EAS label is essentially an LC tank circuit that has a resonance peak anywhere from 1.75 MHz to 9.5 MHz. The most popular frequency is 8.2 MHz. Sensing is achieved by sweeping around the resonant frequency and detecting the dip. Deactivation for 8.2 MHz label tags is achieved by detuning the circuit by partially destroying the capacitor. This is done by submitting the tag to a strong electromagnetic field at the resonant frequency that will induce voltages exceeding the capacitor's breakdown voltage, which is artificially reduced by puncturing the tags.
Microwave Based EAS systems
These permanent tags are made of a non-linear element (a diode) coupled to one microwave and one electrostatic antenna. At the exit, one antenna emits a low-frequency (about 100 kHz) field, and another one emits a microwave field. The tag acts as a mixer remitting a combination of signals from both fields. This modulated signal triggers the alarm. These tags are permanent and somewhat costly. They are mostly used in clothing stores.
Over the past decade, Radio-frequency identification (RFID) technology has become increasingly popular in retail environments. A primary reason for this increase in popularity is it allows for the unique identification of product items, and the writing of data to RFID tags or labels, allowing the collection of item-level intelligence provider great visibility. RFID technology uses communication via radio waves to exchange data between a reader and an electronic tag attached to an object, for the purpose of identification and tracking Some RFID tags can be read from several meters away and beyond the line of sight of the reader. The application of bulk reading enables an almost parallel reading of tags.
Radio-frequency identification involves the use of interrogators (also known as readers), and tags (also known as labels) applied to objects. Most RFID tags contain at least two components. One component is an integrated circuit for storing and processing information, modulating and demodulating a radio-frequency (RF) signal, and other specialized functions. The other component is an antenna for receiving and transmitting the signal.
There are three types of RFID tags: passive RFID tags, which have no power source and require an external electromagnetic field to initiate a signal transmission; active RFID tags, which contain a battery and can transmit signals once an external source (‘Interrogator’) has been successfully identified; and battery-assisted passive (BAP) RFID tags, which require an external source to wake up, but have a significantly higher forward link capability providing greater range.
Today, there are UHF-based RFID hang tags, compliant with the EPC Gen 2 standard, that can be clipped or otherwise embedded within apparel items, and tracked quickly so that all the information about the garment (e.g. the product name, model number, place of origin to its location, etc) can be detected by an RFID (UHF) antenna and displayed on the host computer. The UHF EPC Gen 2 hangtag offers password protection to protect important data in the RFID tag. Using EPC Gen 2 tags, it is possible to better manage processes along the supply chain, in the distribution center, and at the point of sale. Currently, RFID tag products are sold by Checkpoint Systems, and Sensormatic/TYCO, and other vendors described at http://www.rfidtags.com
In an effort to exercise greater control over its supply chain operations, some large retailers, including Walmart, are seeking to require its vendors to apply low-cost RFID tags, encoded with the Electronic Product Code (EPC), to their products in accordance with the EPCglobal Tag Data Standard.
Also, some retail-based systems are now supporting dual or hybrid EAS-RFID tags, that include both (i) an EAS component for item-level security and (ii) an RFID component for real-time inventory control (i.e. visibility). The EAS component, which includes an electromagnetically detectable element, helps prevent theft in the retail store environment. The Item-level RFID component, which stores an electronic product code (EPC) within the tag, drives item level information/intelligence back into the supply chain—to improve existing store operations, increase product availability, and enhance the customer shopping experience.
While EAS tags, RFID tags and hybrid EAS-RFID tags (i.e. Electro-Magnetically Sensible or EMS tags) are often applied to products at the retail side of the value chain, EAS and RFID tags can be applied to products at the source, i.e. the supplier or manufacturer. This is called “source tagging” which, for the retailer, eliminates the labor expense needed to apply the EMS tags themselves, and reduces the time between receipt of merchandise and when the merchandise is ready for sale. For the supplier, the main benefit of source tagging is the preservation of the retail packaging aesthetics by easing the application of security tags within product packaging. Source tagging allows the EM tags to be concealed and more difficult to remove.
Unsolved Problems at the POS Station
U.S. Pat. Nos. 7,172,123; 7,170,414; 6,788,205; 6,764,010 and 6,942,145 describe a number of POS-based checkout systems employing primarily EAS tag deactivation methods.
However, despite recent advances in EAS, RFID and hybrid EAS/RFID systems, shoplifters today can still easily steal an item by the ‘replacing’ or “switching” the barcode of a high-priced item with the barcode taken from a low-priced item, during product checkout operations at the POS station. This can be accomplished in one of several possible ways.
One way to switch prices at the POS station is by taking both a high-priced item and a low priced item to the self-checkout, or a cooperating cashier, and reading the barcode label on the low priced item, while simultaneously passing the high-priced item into the shopping bag (i.e. sweet-hearting).
Another way to switch prices at the POS station is to remove the barcode label from the low-priced item, and place it on the high-priced item, so that when the high-priced item is scanned, the low-priced item barcode will be scanned and read by the POS station.
In both cases described above, the thief is only charged for the low-priced item, and the retail merchant sustains a loss.
While U.S. Pat. No. 7,374,092 to Acosta et al., U.S. Pat. No. 7,495,564 to Harold et al. and U.S. Pat. No. 6,788,205 to Mason et al. each disclose the deployment of EAS tag deactivation coils (i.e. antennas) at the POS station, so that a product's EAS tag can be automatically deactivated upon the successful reading of its barcode label, such POS-based EAS systems fail to provide any way of preventing the above-described theft schemes described above.
Therefore, there still remains a great need in the art for an improved POS-based bar code symbol reading checkout system which is capable of supporting improved levels of electronic article surveillance at the POS station, while avoiding the shortcomings and drawbacks of prior art systems and methodologies.